Got an other one

[bigdaddie47]

Looks like a hydraulic jack of some sort. 27"long, has number  138-8 on the side, no other markings on it. Hook plate rotates around pipe shaft, pointed end appears to slide out. doesn't work yet haven't taken it apart.

[amertrac]

A hydraulic cylindercould have been for almpost  anything from farm machinery to jaws of life  bob w.

[Mac53]

The hook reminds me of a bumper-hook for a hi-lift \ tractor jack. Perhaps an old hydraulic one?

[Aunt Phil]

What ya got there is a mostuv.

That's mostuv a universal hydraulic jack that about 192 different manufacturers made in the late 40s & early 50s trying to take advantage of their new hydraulic knowledge and machining capabilities they came into as military producers until WW II ended.  Everybody was scrambling for a product they could produce and most importantly sell to stay in business.

You put some gentle rust removal technology to that mostuv and make up a toeplate and you just might have one hell of a bumper jack.  It probably won't work well in a horizontal attitude though.